1. Field of the Invention
The present invention relates generally to manifolds for injection molding and, more particularly, to a machined manifold and method of making same for injection molding.
2. Description of the Related Art
Injection molding is a widely known manufacturing process used to produce a variety of parts. Injection molding involves introducing a molten material, for example a molten plastic or resin, into a cavity within a mold until the cavity is filled. The molten material hardens in the mold in the shape of inner surfaces of the cavity. After the molten material hardens or cures, the hardened or cured material is removed from the cavity.
For injection molding, a manifold assembly is typically used for conveying molten material from a central injection portion or sprue to a number of cavities or to multiple points within one large cavity of the mold. An example of such a manifold assembly is disclosed in U.S. Pat. No. 4,964,795 to Tooman. In that patent, a manifold assembly has an integral or one piece, cast, cylindrical manifold with a passageway and at least one nozzle extending radially outwardly from the manifold and having a passageway through which a molten material may pass. The terminal end of the passageway of the nozzle, called a gate, is in fluid communication with the cavity of the mold.
However, it is desirable to provide a manifold assembly that is not cast. It is also desirable to provide a manifold assembly that can be machined from a block or bar. It is further desirable to provide a machined manifold assembly that is generally round or has a generally round or circular cross-sectional shape. Therefore, there is a need in the art to provide a manifold assembly that meets these desires.